1. Field of the Invention
The present invention relates to an imaging device, for example, a digital camera, a camera phone and a portable information device having an imaging function such as a PDA, and an imaging method. More particularly, the present invention relates to an imaging device having a CMOS imaging element enabling high speed continuous shooting.
2. Description of the Related Art
In recent years, an imaging element has been increasingly downsized in order to downsize a digital still camera, and a CMOS (Complementary Metal Oxide Semiconductor) imaging element has been used instead of a conventionally used CCD (Charge Coupled Device) imaging element.
The size of the CMOS imaging element is slightly larger than that of the CCD imaging element, but the CMOS imaging element has an advantage in that it can image at a faster speed than that of the CCD imaging element. In particular, a CMOS imaging element which can shoot up to 240 frames per second is proposed, so that high speed continuous shooting can be performed like a high speed camera.
In high speed continuous shooting, the total number of images to be recorded in a digital still camera is increased. For this reason, it takes time to view a lot of images and to reach a desired image if the images are played back one by one (frame). Accordingly, as a method of displaying images obtained by high speed continuous shooting, it is general to continuously play back the continuously-shot images.
As a method of displaying images obtained by high speed continuous shooting, a technique, which continuously plays back images at a speed according to a shutter speed in shooting, is proposed in JP2005-176246A and JP H05-224287A.
For example, when shooting a milkcrown phenomenon in which a crown shape is formed when a water drop falls in viscous liquid such as milk as illustrated in FIG. 1, it is general to perform continuous shooting in order to definitely capture a moment when the phenomenon occurs.
However, the technique described in JP2005-176246A and JP H05-224287A has the following problem. When continuously playing back continuously-shot images, the moment when the milkcrown phenomenon illustrated in FIG. 1 (4) occurs may be continuously played back at high speed.
On the other hand, when continuously playing back images at low speed in order to confirm the milkcrown phenomenon, time may be wasted till the moment that the milkcrown phenomenon is played back because the milkcrown phenomenon occurs in a short time relative to the total shooting time (total playback time). Accordingly, a technique which can play back a desired image (milkcrown phenomenon) at low speed, and fast-forward the other images (high speed playback) is desired.